杉木幼林地水土流失规律的研究

STUDIES ON THE LAW OF THE SOIL AND WATER LOSSES IN THE CULTURAL LAND OF CHINESE FIR

在4个坡度级的山场上建立12个径流小区,连续4年对炼山的杉木幼林地定位观测,分析了杉木幼林从炼山起至郁闭止,林地的水、土、肥流失的季节和年度的变化规律,划分了水土流失时期,分析坡度与流失的关系。结果指出,炼山后第一年水、土、肥流失最严重,泥沙冲刷量达24.81t·ha^(-1),以后逐年递减,至第4年趋于稳定,与不炼山的接近。常规幼林抚育措施加剧了林地水土流失,建议调整幼林抚育方式和季节,并采取必要的生物措施。

12 nunoff plats were set up in mountain timber yards at four classes ofslope (e, g. 8,19, 24, 32), the fired position observations of the cultural land ofChinese fir had been continued for 4 years after control burning. The laws ofseasonal and annual changes in water,soil and nutrient losses of the forest landwere analysed from the control burning to canopy closure of Chinese fir cu-ltural land. The periods of soil and water losses were divided. The relation-ship between slope and loss was also analysed. The results indicated that run-off, soil and nutrient losses were most serious in the first year after controlburning, in which the amount of soil erosion was up to 24.81t/ha, then thelosses decreased yearly, and tend to[steadiness until the fourth year, which wassimilar to]that in the sites not to be burned. The common measure of culturaloperations aggrevated the amount of soil erosion. The authors suggest to adjustthe fashion and season of cultural operations, and adopt necessary biologicalmeasures.